Multi-wheeled excavator and conveying system

ABSTRACT

An excavating and loading system includes an excavating wheel assembly and a plurality of conveyors. The excavating wheel assembly comprises three excavating wheels having an overall width in excess of that of the remainder of the system. Each excavating wheel includes a plurality of digging buckets each comprising a wall supported for pivotal movement between a material receiving position and a material dumping position. The excavating wheel assembly is supported at the front end of a vehicle on a subframe mounted for pivotal movement relative to the vehicle and is driven by an engine which is also supported on a subframe. The conveyors of the excavating and loading system include cross conveyors and a main conveyor for receiving material from the excavating wheels. The main conveyor transports the material rearwardly from the excavating wheel assembly and delivers the material from the opposite end of the vehicle. An auxiliary conveyor assembly is detachably supported at the opposite end of the vehicle to receive material from the main conveyor and to transport the material either laterally or rearwardly. Ballast tanks are located at spaced points on the vehicle to selectively receive liquid and thereby counterbalance the weight of the auxiliary conveyor. All of the components of the system other than the excavating wheel assembly are activated by an engine mounted on the vehicle.

United States Patent 1191 Satterwhite 1 1 MULTI-WHEELED EXCAVATOR AND CONVEYING SYSTEM [76] Inventor: Charles R. Satterwhite, 10031 Venitian Way, Dallas, Tex. 75229 [22] Filed: Jan. 21, 1974 [21] Appl. No.: 435,296

Related U.S. Application Data [63] Continuation of Ser. No. 238,089, March 27, 1972,

abandoned.

[52} U.S. Cl. 371190; 37/D1G. 2; 198/9; 198/100; 198/109; 299/67; 299/76; 299/78 [51] Int. Cl E02f 3/18 [58] Field 01 Search 37/189, 190, 91, 94-97, 37/D1G. 2; 198/100, 109, 9', 299/73, 76, 77, 78, 64-68 {56} References Cited UNITED STATES PATENTS 400,154 3/1889 Williams 37/25 818,215 4/1906 Anderson................................37/95 853,985 5/1907 Linga 37/94 892,056 6/1908 Jackson 37/189 1,083,897 1/1914 Lee 37/96 1,092,632 4/1914 Crain 172/96 1,143,897 6/1915 Flexner et a1 299/76 1,148,975 8/1915 Kuhn et a1. 299/77 1,210,412 1/1917 Budlong 37/87 1,336,657 4/1920 Schmidt... 37/189 1,414,201 4/1922 Pederson 198/9 1,448,579 3/1923 Tideman 172/546 1,455,206 5/1923 Howe, et al.. 37/97 1,581,685 4/1926 Oldroyd 198/9 1,679,143 7/1928 Wineman.. 198/9 1,716,390 6/1929 Swanson... 37/45 1,858,327 5/1932 Hays 37/190 X 2,528,012 10/1950 Mensforth. 198/9 2,648,422 8/1953 Kling 198/100 X 2,691,262 10/1954 Swertfeger... 172/45 2,695,164 11/1954 Arentzcn 299/71 2,696,287 12/1954 Foust..... 198/109 X 2,711,035 6/1955 Pitts 37/97 2,732,641 l/1956 .lespersen.. 37/189 2,744,741 5/1956 Spigarelli.. 299/76 2,748,505 6/1956 Turner 37/96 2,834,128 5/1958 Kolbe 37/189 2,926,438 3/1960 Kolbe 37/190 3,043,035 7/1962 Fogelberg 37/190 3,052,455 9/1962 McLaughlin et 31.... 299/76 3,091,874 6/1963 Wuigk 37/190 3,109,636 11/1963 Hlinsky 299/6 [451 July 29, 1975 3,731,408 5/1973 Neal 37/91 FOREIGN PATENTS OR APPLICATIONS 251,471 7/1970 U.S.S.R. 590,853 lll934 Germany 809,260 8/1936 France 919,031 ll/1946 France 137.833 10/1956 U.S.S.R 37/190 992.676 5/1965 United Kingdom. 37/190 900,556 12/1953 Germany 37/190 Primary ExaminerClifford D. Crowder Attorney, Agent, or Firm-Richards, Harris 8L Medlock [57] ABSTRACT An excavating and loading system includes an excavating wheel assembly and a plurality of conveyors. The excavating wheel assembly comprises three excavating wheels having an overall width in excess of that of the remainder of the system. Each excavating wheel includes a plurality of digging buckets each comprising a wall supported for pivotal movement between a material receiving position and a material dumping position. The excavating wheel assembly is supported at the front end of a vehicle on a subframe mounted for pivotal movement relative to the vehicle and is driven by an engine which is also supported on a subframe. The conveyors of the excavating and loading system include cross conveyors and a main conveyor for receiving material from the excavating wheels. The main conveyor transports the material rearwardly from the excavating wheel assembly and delivers the material from the opposite end of the vehicle. An auxiliary conveyor assembly is detachably supported at the opposite end of the vehicle to receive material from the main conveyor and to transport the material either laterally or rearwardly. Ballast tanks are located at spaced points on the vehicle to selectively receive liquid and thereby counterbalance the weight of the auxiliary conveyor. All of the components of the system other than the excavating wheel assembly are activated by an engine mounted on the vehicle.

44 Claims, 13 Drawing Figures mgmgmmzems FIG! FIG. 2

PATENTED JUL 29 1975 PATENTEU JUL29 1975 FIG. /3

MULTl-WHEELED EXCAVATOR AND CONVEYING SYSTEM This is a continuation of application Ser. No. 238,089, filed Mar. 27, 1972, now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to an excavating and loading system, and more particularly to an improved excavating and loading system of the type incorporating an excavating wheel.

Although an almost infinite number of excavating and loading systems have been designed heretofore, the need persists for considerable improvement in the art. For example, a typical loading machine available at the present time is capable of loading up to 1,700 cubic yards of earth per hour, has a gross weight of approximately 250,000 pounds, and sells for approximately $330,000. Furthermore, notwithstanding this relatively high cost and relatively low capacity, such a device is incapable of either ditching or forming a finished grade.

The present invention comprises a novel excavating and loading system which overcomes the disadvantages that have characterized the prior art. Thus, the preferred embodiment of the invention comprises a machine capable of loading up to 4,000 cubic yards of earth per hour, having a gross weight of about 100,000

pounds, and having a selling price of approximately $150,000. Perhaps more importantly, excavating and loading systems incorporating the invention are capable of forming a finished grade in a single pass.

In accordance with the broader aspects of the invention, an excavating and loading system comprises a vehicle, an excavating wheel assembly mounted at one end of the vehicle, and a conveyor which extends upwardly from a material receiving portion adjacent the wheel assembly to a material delivery portion at the opposite end of the vehicle. The excavating wheel assembly is greater in width than the remaining components of the system and comprises a plurality ofdigging buckets each including a wall which is supported for pivotal movement between a material receiving position and a material dumping position. Structure is provided for rotating the excavating wheel assembly and for operating the movable walls of the buckets to first receive material and to subsequently dump the material into the material receiving portion of the conveyor.

In accordance with the more specific aspects of the invention, the vehicle comprises a main frame which is supported by a plurality of tired wheels. A first engine is supported on the main frame and functions to actuate the wheels to propel the vehicle and to actuate the conveyor to transport material thereon from the material receiving portion to the material delivery portion. A subframe is mounted at the forward end of the main frame and the excavating wheel assembly is rotatably supported on the subframe. The subframe also supports a second engine and a transmission which operatively interconnects the second engine and the excavating wheel assembly. An auxiliary conveyor is detachably supported at the rear of the main frame for receiving material from the delivery end of the conveyor and for transporting the material either rearwardly or laterally. A plurality of ballast tanks are mounted on the main frame for receiving liquid to counterbalance the weight of the auxiliary conveyor.

The excavating wheel assembly preferably comprises a center wheel and a pair of side wheels which are supported on the subframe for rotation about a common axis. In such a case cross conveyors are provided for transporting material from the side wheels to the material receiving portion of the main conveyor. The first engine preferably drives hydraulic pumps. This permits actuation of the propelling wheels, the main conveyor, the auxiliary conveyor, the auxiliary conveyor positioning means, and the cross conveyors by hydraulic motors operatively connected to the pumps.

In accordance with an alternative embodiment of the invention, a motor is mounted on the subframe instead of the second engine. the vertical positioning of the material delivery portion of the main conveyor is lowered, and the auxiliary conveyor is removed. Structure is provided for pivoting the subframe to position the excavating wheel above and below the highest and lowest elements of the system, respectively. This permits use of the excavating and loading system in tunneling operations.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the invention may be had by referring to the following Detailed Description when taken in conjunction with the accompanying Drawings, wherein:

FIG. 1 is a side view of an excavating and loading sys tem comprising the preferred embodiment of the invention;

FIG. 2 is a partial top view of the excavating and loading system shown in FIG. 1',

FIG. 3 is a partial front view of the excavating and loading system;

FIGS. 4, 5, and 6 are enlarged side views of the rear. central, and forward portions of the excavating and loading system, respectively;

FIGS. 7 through 12 are illustrations of various systems for actuating the rear plates of the digging buckets of an excavating and loading system incorporating the invention; and

FIG. 13 is a side view of an excavating and loading system comprising an alternative embodiment of the invention.

DETAILED DESCRIPTION Referring now to the Drawings, and particularly to FIGS. 1 and 4 through 6, an excavating and loading system 20 incorporating the preferred embodiment of the invention is shown. The system 20 comprises a vehicle 22 including a main frame 24 which is supported by four wheels 26 for movement along a surface S. Each of the wheels 26 comprises a pneumatic tire 28 whereby the excavating and loading system 20 is adapted for movement over highways and other paved surfaces as well as for operation in unpaved areas, such as during an excavating operation.

A first engine 30 is supported on the main frame 24 of the vehicle 22. In accordance with the preferred embodiment of the invention, the first engine 30 is an internal combustion engine and functions to drive a plurality of hydraulic pumps 32. The pumps 32 in turn supply operating power for various components of the excavating and loading system 20. For example, one of the pumps 32 supplies operating power for a hydrostatic drive 34. The hydrostatic drive 34 is coupled to a transmission 36 including a brake 38. The transmission 36 provides dual outputs which are coupled to a forward differential 40 and a rear differential 42 by a plurality of drive shafts 44. Thus, the hydrostatic drive 34 operates by means of the wheels 26 to propel the excavating and loading system both during excavating operations and during travel.

An excavating system 50 comprises the forward portion of the excavating and loading system 20. The excavating system 50 includes a subframe 52 which is sup ported on a shaft 54 for pivotal movement relative to the vehicle 22 under the action of a pair of hydraulic cylinders 56. Operating power for the cylinders 56 is supplied by one of the pumps 32 which are driven by the first engine 30.

The excavating system 50 further includes an area vating wheel assembly 58 which is supported at the front end of the subframe 52. The excavating wheel assembly 58 is driven by a second internal combustion engine 60 which is supported at the rear end of the subframe 52. The engine 60 provides operating power for the excavating wheel assembly 58 but otherwise plays no part in the operation of the excavating and loading system 20. This arrangement has been found to be highly satisfactory for two reasons. First, it permits selection of the second engine 60 on the basis of the power requirements of the excavating system 50 only and not on the basis of the power requirements of the other components of the excavating and loading system 20. Also. due to its positioning at the rear of the subframe 52, the second engine 60 acts as a counterbalance for the weight of the excavating wheel assembly 58. This permits the use of hydraulic cylinders 56 of reduced size and also reduces the amount of power that is required in manipulating the excavating wheel assembly 58.

As is best shown in FIG. 6, a crumbing shoe 62 is supported at the front end of the vehicle 22 of the excavating and loading system 20 beneath the excavating wheel assembly 58. The crumbing shoe 62 is connected to the vehicle 22 by a pair of turnbuckles 64 and is also connected to the subframe 52. By this means the positioning of the subframe 52 under the action of the hydraulic cylinders 56 automatically correctly positions the crumbing shoe 62.

Referring now to FIGS. 2, 3, and 6, the excavating wheel assembly 58 comprises three excavating wheels 66A, 66B. and 66C, which are rotatably supported on the subframe 52 by a shaft 68 and a plurality of bushings 70. The second engine 60 drives a speed reducer 72 which in turn drives a right angle drive 74. The right angle drive 74 actuates a pair of chain and sprocket drives 76 each including a sprocket 78 driven by the right angle drive 74, a chain 80 driven by the sprocket 78, and a sprocket 82 driven by the chain 80. As is best shown in FIG. 2, the chains 80 and the sprockets 82 are mounted within the subframe 52, which constitutes a housing, and are therefore protected from damage to accumulations of dirt, etc. during the operation of the excavating and loading system 20.

Each sprocket 82 is mounted on a shaft 84 which is rotatably supported in the subframe 52 and which in turn supports a pair of pinions 86. The pinions 86 are each mounted in mesh with a ring gear 88 mounted on one of the wheels 66 whereby the second engine 60 functions to rotate the wheels. in accordance with the preferred embodiment of the invention. the center excavating wheel 66B is provided with two ring gears 88 and is driven by two pinions 86, whereas the side exca vating wheels 66A and 66C support a single ring gear 88 and are driven by a single pinion 86.

The excavating wheels 66 of the excavating wheel assembly 58 each includes a hub 90 and a pair of rims 92 which extend radially outwardly from the hub. The excavating wheels comprise a plurality of digging buckets 94 which are equally spaced circumferentially around the hub 90 and which extend between the rims 92. The digging buckets 94 each have a cutting edge 96 including a plurality of teeth 98 and a stationary front wall 100 extending generally radially inwardly from the cutting edge 96. Each digging bucket further includes a rear wall 102 which is supported for pivotal movement between a digging position and a dumping position. The rear walls 102 of the digging buckets 94 are actuated by one of the mechanisms shown in FIGS. 7 through 12 and are manipulated thereby to the digging position when their respective digging buckets 94 are in the lower and forward portion of their rotary motion and to the dumping position when their respective digging buckets are in the upper and rearward portion of their rotary motion.

As is clearly shown in FIGS. 2 and 3, the three wheels 66A, 66B, and 66C comprising the excavating wheel assembly 58 have an overall width which exceeds that of the remaining components of the excavating and loading system 20. This has been found to be highly advantageous for two reasons. First, by increasing the width of the excavating wheel assembly 58 over that of a conventional ditching machine, an excavating and loading system incorporating the present invention is capable of excavating considerably more material without increasing the speed of rotation of the excavating wheel assembly. Second, the fact that the excavating wheel assembly 58 is wider than the remaining components of the excavating and loading system 20 permits operation of the excavating and loading system within the excavation that is being formed. This materially reduces the amount of movement of the excavating wheel assembly 58 that is necessary to position the assembly for excavating and for travel, and thereby reduces the overall complexity of an excavating and loading system incorporating the invention.

The excavating and loading system 20 further includes a loading system 110. The loading system includes a main conveyor 112 comprising an endless belt 114 mounted for movement around a course extending angularly upwardly relative to the main frame 24 of the vehicle 22 and including a material receiving portion 116 and a material delivery portion 118. More particularly, the course of the belt 114 is defined by a plurality of rollers 120 which are supported on a conveyor frame 122. The conveyor frame 122 is supported on the main frame 24 of the vehicle 22 and includes an upper portion 124 supported for pivotal movement about a horizontal axis under the action of a hydraulic cylinder 126. This permits control over the vertical positioning of the material delivery portion 118 of the conveyor 112.

The belt 114 of the main conveyor 112 extends around a relatively small drum 128 mounted at the upper end of the frame 122 and around a relatively large drum 130 mounted on the frame 24. The drums 128 and 130 are rotated by radial hydraulic motors 132 and 134, respectively. By this means the belt 114 is actuated for movement around the course defined by the rollers to move material from the material receiving portion 116 to the material discharge portion 118. It has been found that the positioning of the drums 128 and 130 causes a synergistic effect in that the drum 130 functions to cause the belt 114 to wrap more tightly around the drum 128 and thereby increase the effectiveness of the motor 132 in moving the belt 114.

A pair of cross conveyors are also supported on the main frame 24 of the vehicle 22. The cross conveyors 140 are driven by hydraulic motors 142 and func tion to receive material from the side excavating wheels 66A and 66C and to deliver the material to the material receiving portion 116 of the main conveyor 112. By this means all material that is excavated by the excavating wheel assembly 58 is delivered to the main conveyor 112 for transportion thereby from the material receiving portion 116 to the material discharge 118.

Referring now particularly to FIGS. 1 and 4, the preferred embodiment of the invention further includes an auxiliary conveyor system 150. The auxiliary conveyor system includes a frame 152 which is secured to the rear end of the frame 24 of the vehicle 22 by a plurality of pins 154. A turntable 156 is supported on the frame 152 for pivotal movement about a vertical axis under the action of a hydraulic motor 158.

A conveyor 160 is supported on the turntable 156 to receive material discharged from the material discharge portion 118 of the main conveyor 112. The conveyor 160 comprises a frame 162 which is supported on the turntable 156 and an endless belt 164 mounted for movement around a course defined by a plurality of rollers 166. The belt 164 is driven by a radial hydraulic motor 168, and a hydraulic cylinder is provided for controlling the angular relationship of the frame 162 to the turntable 156.

The auxiliary conveyor system 150 further includes a stringer conveyor 172 comprising a frame 174 which is supported on the frame 162 of the conveyor 160 by a pair of parallel links 176. An endless belt 178 is supported on the frame 174 for movement around a course defined by a pair of drums 180. The conveyor 178 is driven by small hydraulic motors (not shown) mounted in the drums 180.

A hydraulic cylinder 182 extends between the frame 162 of the conveyor 160 and the frame 174 of the conveyor 172 for actuation to manipulate the conveyor 172 between the positions shown in full and in dashed lines in FIG. 4. When the conveyor 172 is positioned as shown in full lines in FIG. 4, it functions to receive material from the conveyor 160 and to discharge the material from the end of the excavating and loading system 20 remote from the excavating system 50. On the other hand, when the conveyor 172 is positioned as shown in dashed lines in FIG. 4 material is discharged directly from the conveyor 160. This arrangement is highly advantageous in that it permits the positioning of a dump truck or similar vehicle under the discharge end of the conveyor 160 while another vehicle is being loaded from the conveyor 172, and vice versa.

It will be appreciated that the hydraulic motor 158 may be actuated to pivot the turntable 156 and the con veyors 160 and 172 supported thereon through an arc of approximately The excavating and loading system 20 may also be operated with the auxiliary conveyor system 150 removed, ifdesired. These conditions cause substantial changes in the overall weight distribution of the component parts of the excavating and loading system 20.

As is best shown in FIGS. 1 and 2, the vehicle 22 is equipped with a counterbalancing system comprising four ballast tanks 192, 194, 196, and 198 located at forward and rearward positions on opposite sides of the vehicle 22. In the use of the excavating and loading system 20, water is selectively pumped to and from the tanks comprising the counterbalancing system 190 whereby changes of the weight distribution of the excavating and loading system 20 caused by manipulations of the auxiliary conveyor system 150 are compensated for. Thus, ifthe excavating and loading system 20 is operated with the auxiliary conveyor system 150 removed, water is pumped out of the tanks 194 and 198 and into the tanks 192 and 196. Similarly, if the hydraulic motor 158 is operated to pivot the auxiliary conveyor system 150 towards one side of the vehicle 22, the tanks on the opposite side of the vehicle are filled with water whereby the change in weight distribution caused by the manipulation of the auxiliary conveyor system 150 is completely counterbalanced.

All of the hydraulic motors and all of the hydraulic cylinders comprising the loading system 110 are operatively connected to the pumps 32 which are driven by the first engine 30. Thus. the excavating and loading system 20 comprises separate excavating and loading systems 50 and 110, respectively. which are driven by independent power sources. This arrangement has been found to be advantageous in that it permits optimum utilization of both systems. For example, in certain instances it may be necessary to provide maximum operating power to the excavating system 50 and to simultaneously provide maximum operating power to the loading system 110. Such a situation is accommodated much more readily by means of the present invention than would otherwise be possible.

Various systems for actuating the rear walls 102 of the digging buckets 94 of the excavating wheels 66A. 66B, and 66C are shown in FIGS. 7 through 12. Referring particularly to FIG. 7, an actuating system 200 comprises a plurality of push rods 202 each of which is connected between one of the rear walls 102 and a chain 204. The chain 204 is generally unconstrained but extends around a roller 206 which is supported on the shaft 68 and which is secured against angular movement relative to the shaft 68 by suitable brackets (not shown). As the digging wheels are rotated about the shaft 68 under the action of the second engine 60, each push rod 202 comes into engagement with the roller 206 whereupon its respective rear wall 102 is pushed outwardly to the material dumping position. Subsequently, as each digging bucket is rotated to the lower and forward portion of its circular path, the chain operates through the push rod 202 to positively return the rear wall 102 to the material digging postion. This positive actuation of the rear wall 102 in both directions has been found to be vastly superior to the arrangement that has been used heretofore wherein the rear portions were allowed to return to the digging position under the action of gravity.

An actuating system 208 that is similar in many respects to the system 200 is shown in FIG. 8. The system 208 incorporates a plurality of push rods 210 each connected between a chain 212 and the rear wall 102 of one of the digging buckets 94. The principal difference between the system 208 and the system 200 is that the chain 212 of the system 208 is equipped with a plurality of rollers 214. The rollers 214 are mounted for movement around a saddle 216 which is fixed to the shaft 68. By this means the rear wall 102 of the digging buckets 94 are positively actuated to the dumping position as each bucket is rotated to the upper and rearward por tion of its circular path and is positively returned to the digging position as the bucket is rotated to the lower and forward portion of its path.

Another actuating system 218 is shown in H6. 9. The system 218 includes a crank 220 which is fixed to the shaft 68. A collar 222 is rotatably supported on the crank 220, and a plurality of push rods 224 extend from the collar 222 to the rear walls 102 of the digging buckets 94. One of the rear walls 102 is connected to the collar 222 by a rod 226 which is fixed to the collar 222. By this means the collar 222 is constrained for rotation with the digging wheel whereby the push rods 224 and 226 function to positively actuate the rear walls 102 to the dumping position when their respective digging buckets are in the upper and rearward portion of their travel about the shaft 68 and to positively return the rearward walls 102 to the digging position when their respective digging buckets are in the lower and forward portion of their travel.

Still another actuating system 228 is shown in FIG. 10. The system 228 comprises a plurality of cams 230 each fixed to one of the rear walls 102 of the digging buckets 94. The cams 230 are positioned for engagement with a roller 232 which is supported on an arm 234 that is fixed to the shaft 68. Each rear wall 102 is also provided with a spring 236 which functions to return the rear wall 102 to the digging position. Thus, upon rotation of a particular digging bucket to bring its cam 230 into engagement with the roller 232, the rear wall 102 of the digging bucket is actuated to the dumping position. As soon as the cam 230 comes out of engagement with the roller 232, the spring 236 returns the rear wall 102 to the digging position.

Referring now to FIG. 11, an actuating system 238 is shown. The system 238 comprises a cam track 240 which is supported on the shaft 68 and which is fixed against rotation with respect thereto. The rear wall 102 of each digging bucket 94 is equipped with a cam follower 242 including a roller 244 mounted in the cam track 240. The shape of the cam track 240 is such that each rear wall 102 is actuated to the dumping position when its digging bucket 94 is in the upper and rearward portion of its rotation about the shaft 68 and is returned to the digging position when its respective bucket 94 is in the lower and forward portion of its rotation.

Yet another actuating system 246 is shown in FIG. 12. In accordance with the system 246 a pneumatic cylinder 248 is provided for actuating the rear wall 102 of each digging bucket 94 between the digging and the dumping positions. Each pneumatic cylinder 248 is equipped with a valve 250 for controlling the flow of compressed air from a manifold 252 to the cylinder 248. Each valve 250 is in turn equipped with a cam follower 254 which functions to open its respective valve whenever it is moved inwardly.

The cylinders 248 and their respective valves 250 are mounted for rotation about the shaft 68 with the digging buckets 94 comprising the excavating wheels. A cam 256 is supported in fixed relation to the shaft 68. Thus, as each digging bucket rotates in alignment with the cam 256, its respective cam follower 254 is actuated by the cam 256. This operates the corresponding valve 250 to admit compressed air to its pneumatic cylinder 248, whereupon the rear wall 102 is actuated to the dumping position. In a particular arrangement shown, the rear walls 102 of the digging buckets 94 are returned to the digging position by individual springs 258. However, it will be understood that the actuating system 246 may be modified to provide for return of the rear walls 102 under pneumatic action, if desired. it will be further understood that the cylinders 248 can comprise hydraulic cylinders rather than pneumatic cylinders.

Referring now to FIG. 13, an excavating and loading system 20' comprising a second embodiment of the invention is shown. The excavating and loading system 20 is similar to the excavating and loading system 20 described hereinbefore in that it comprises a vehicle 22', an excavating system 50', and a loading system One difference between the system 20 and the system 20' is that the first and second engines 30 and 60 of the system 20 are replaced with electric motors 30' and 60' in the system 20'. Another difference is that the electric motor 60' is positioned in a forward location and in that the angular positioning of the excavating system 50 is controlled by hydraulic cylinders 56' which are arranged somewhat differently from the hydraulic cylinders 56 of the excavating and loading system 20. This permits the cylinders 56' to pivot the excavating system 50' to points above and below the highest and lowest points on the remainder of the excavating system 20' and thereby adapts the excavating and loading system 20' to tunneling operations. The use of the excavating and loading system 20 in tunneling operations is further facilitated by the use of the electric motors 30' and 60' whereby the emission of dangerous exhaust gases is completely eliminated.

From the foregoing it will be understood that the present invention comprises an excavating and loading system including an excavating wheel assembly mounted at one end of the vehicle and a conveyor which extends upwardly from a material receiving portion adjacent the wheel to a material delivery portion at the opposite end of the vehicle. The use of the invention is advantageous over prior art systems in that an excavating and loading system incorporating the invention can be constructed at lower cost and yet has greater capacity than is the case with the various prior art excavating and loading systems. Furthermore, an excavating and loading system incorporating the present invention is adapted to provide a finished grade in a single pass and thereby eliminates the need for auxiliary finishing equipment of the type that has heretofore been required to complete excavations made by an excavating and loading system.

More specifically, one of the major advantages in the use of the present invention involves the width of the excavating wheel assembly which is in excess of that of the remainder of the system. This feature in combination with the rearward or outward unloading of the digging buckets permits operation of an excavating and loading system incorporating the invention to form a ditch having a depth equal to the diameter of the excavating wheel assembly. Also, structure may be secured to the excavating wheel assembly for rotation therewith to form tapered side walls on such a ditch. Both of these operational modes are impossible in the case of a machine having either supporting structure or loading apparatus positioned laterally of the excavating wheel.

Although preferred embodiments of the invention have been illustrated in the Drawings and described in the foregoing specification, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of rearrangement, modification, and substitution of parts and elements without departing from the spirit of the invention.

What is claimed is:

1. An excavating and loading system comprising:

an excavating wheel assembly comprising axle means and at least two rigid excavating wheels rotatably mounted cantilever on and supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system;

each of said excavating wheels including a plurality of digging buckets located immediately adjacent one another to define the entire circumference of the excavating wheel, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position;

supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly;

each of said digging buckets extending continuously between a side wall thereof located immediately adjacent to the supporting means and a side wall thereof defining one end of the excavating wheel assembly;

drive means extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path;

means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each digging bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path;

a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; and

conveyor means mounted on the vehicle entirely behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from the digging buckets of the excavating wheels upon the positioning of the movable walls of the buckets in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the low portion.

2. The excavating and loading system according to claim 1 wherein the excavating wheel assembly is further characterized by a third rigid excavating wheel positioned between the said at least two excavating wheels and rotatably supported on the axle means.

3. The excavating and loading system according to claim 2 wherein the conveyor means receives excavated material directly from the center excavating wheel and further including means positioned on the vehicle behind the excavating wheel assembly to receive excavated material from the digging buckets of the outside excavating wheels upon positioning of the movable walls of the digging buckets in the material dumping position and for directing the material to the conveyor means.

4. The excavating and loading system according to claim 1 further including a third excavating wheel supported on the axle means between the two cantilever supported excavating wheels and wherein the excavating wheel supporting and driving means comprises spaced, parallel excavating wheel supporting and driving means extending between the center and the two side excavating wheels.

5. The excavating and loading system according to claim 4 wherein the conveyor means receives material from the center excavating wheel and further including means mounted on the vehicle behind the excavating wheel means for receiving material from the two side excavating wheels and for directing the material to the conveyor means for transportation thereby to the discharge point.

6. The excavating and loading system according to claim 1 further including a conveyor frame supported on the main frame of the vehicle and extending angularly upwardly with respect thereto to define a course of the conveyor means. means supporting the upper portion of the conveyor frame for pivotal movement with respect to the lower portion thereof. an auxiliary conveyor supported at the rear end of the system for receiving material from the conveyor means. and means supporting the auxiliary conveyor for pivotal movement about a vertical axis.

7. The excavating and loading system according to claim 1 further including a ballast system comprising a plurality of tanks positioned at spaced points on the vehicle and means for selectively pumping liquid between the tanks.

8. The excavating and loading system according to claim 1 wherein the movable wall pivoting means comprises:

a plurality of push rods each connected at one end to the movable wall of one of the buckets;

a chain interconnecting the ends of the push rods remote from the movable walls; and

a member fixedly supported at a point over the material receiving portion of the conveyor means for cooperation with each push rod to move the corresponding movable wall to the material dumping position.

9. The excavating and loading system according to claim 1 wherein the movable wall pivoting means comprises:

a plurality of push rods each connected at one end to the movable wall of one of the buckets;

a collar connected to the ends of the push rods remote from the movable walls;

means constraining the push rods to rotation with the buckets; and

means rotatably supporting the collar at a point offset from the axis of rotation of the buckets and thereby actuating the push rods to pivot the movable walls to the material dumping position when their respective buckets are positioned over the material receiving portion of the conveyor means.

10. The excavating and loading system according to claim 1 wherein the movable wall pivoting means c0mprises:

a spring connected to each movable wall for normally positioning the movable wall in the material receiving position;

a cam mounted on each movable wall; and

means positioned over the material receiving portion of the conveyor means for cooperation with the cams on the movable walls to pivot the movable walls to the material dumping position against the action of the springs.

11. The excavating and loading system according to claim 1 wherein the movable wall pivoting means further comprises:

a cam track disposed around the axis of rotation of the buckets; and

a plurality of cam followers each connected to one of the movable walls and each operatively engaged with the cam track for actuation thereby to pivot the movable walls between the material receiving and the material dumping positions.

12. The excavating and loading system according to claim 1 wherein the movable wall pivoting means coniprises:

a plurality of cylinders each connected to one of the movable walls for actuation under fluid pressure to pivot the movable walls to the material dumping position; and

valve means for controlling the actuation of the cylinders in accordance with the rotational positioning of the digging buckets.

13. The excavating and loading system according to claim 1 further including:

auxiliary conveyor means mounted on the vehicle for receiving excavated material from the conveyor means and mounted for pivotal movement about a vertical axis;

a plurality of ballast tanks; and

means for selectively directing liquid between the ballast tanks to counterbalance the weight of the auxiliary conveyor means.

14. The excavating and loading system according to claim 13 wherein the vehicle further comprises:

a frame;

means supporting the frame for movement along a surface; and

an engine for actuating the supporting means to propel the vehicle and for actuating the conveyor means and the auxiliary conveyor means;

and wherein the ballast tanks are further characterized by four ballast tanks positioned at forward and rearward positions on opposite sides of the frame.

15. The excavating and loading system according to claim 14 wherein the excavating wheel means is positioned at one end of the frame, wherein the conveyor means extends rearwardly from the frame between the ballast tanks, and wherein the auxiliary conveyor means is positioned at the opposite end of the frame from the excavating wheel means.

16. The excavating system according to claim 1 wherein the conveyor means comprises a pair of cross conveyors mounted on the vehicle adjacent the excavating wheels for receiving material from the excavating wheels and for transporting the material inwardly and a conveyor centrally disposed on the vehicle for re ceiving material from the cross conveyors and from the excavating wheels and for transporting the material angularly upwardly to a discharge point at the opposite end of the vehicle from the excavating wheels.

l7. An excavating and loading system comprising:

an excavating wheel assembly comprising axle means and three rigid excavating wheels rotatably supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system;

each of said excavating wheels including a plurality of digging buckets, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position;

supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly;

said three excavating wheels including a center excavating wheel comprising digging buckets spanning continuously between points immediately adjacent to the supporting and housing means and two side excavating wheels each comprising digging buckets spanning continuously from points immediately adjacent to the supporting and housing means to points defining the outer ends of the excavating wheel assembly;

means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path;

means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path;

a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated;

conveyor means mounted on the vehicle behind the excavating wheel for movement around a course including a relatively low portion positioned to receive material from each digging bucket of the center excavating wheel upon the positioning of the movable wall of the bucket in the material dumping position and a relatively high material delivery por tion located rearwardly on the vehicle from the lower portion; and

means positioned on the vehicle behind the excavating wheel assembly to receive material from each digging bucket of the outside excavating wheels upon the positioning of the movable wall of the bucket in the material dumping position and for directing the material to the conveyor means.

18. The excavating and loading system according to claim 17 wherein the conveyor means is further characterized by a conveyor frame mounted on the vehicle and extending generally angularly upwardly with respect thereto to define the course of the conveyor means and including a lower fixedly supported portion and an upper portion mounted for pivotal movement about a horizontal axis.

19. The excavating and loading system according to claim 17 further including an auxiliary conveyor mounted beneath the high delivery portion of the conveyor means for receiving material therefrom, and

means for selectively pivoting the auxiliary conveyor about a vertical axis.

20. The excavating and loading system according to claim 17 wherein the vehicle comprises:

a main frame;

a plurality of pneumatic tired wheels for supporting the main frame; and

an engine mounted on the main frame for propelling the system by means of the wheels and for actuating the conveyor means independently of the operation of the excavating wheel supporting and rotating means.

21. The excavating and loading system according to claim 17 further including a conveyor frame supported on the main frame of the vehicle and extending angularly upwardly with respect thereto to define a course of the conveyor means, means supporting the upper portion of the conveyor frame for pivotal movement with respect to the lower portion thereof, an auxiliary conveyor supported at the rear end of the system for receiving material from the conveyor means, and means supporting the auxiliary conveyor for pivotal movement about a vertical axis.

22. The excavating and loading system according to claim 21 further including a ballast system comprising a plurality of tanks positioned at spaced points on the vehicle and means for selectively pumping liquid between the tanks and thereby counterbalancing the weight of the auxiliary conveyor.

23. The excavating and loading system according to claim 17 wherein the movable wall pivoting means comprises:

a plurality of push rods each connected at one end to the movable wall of one of the buckets;

a chain interconnecting the ends of the push rods remote from the movable walls; and

a member fixedly supported at a point over the material receiving portion of the conveyor means for cooperation with each push rod to move the corresponding movable wall to the material dumping position.

24. The excavating and loading system according to claim 17 wherein the movable wall pivoting means comprises:

a plurality of push rods each connected at one end to the movable wall of one of the buckets;

a collar connected to the ends of the push rods remote from the movable walls;

means constraining the push rods to rotation with the buckets; and

means rotatably supporting the collar at a point offset from the axis of rotation of the buckets and thereby actuating the push rods to pivot the movable walls to the material dumping position when their respective buckets are positioned over the material receiving portion of the conveyor means.

25. The excavating and loading system according to claim 17 wherein the movable wall pivoting means comprises:

a spring connected to each movable wall for normally positioning the movable wall in the material receiving position;

a cam mounted on each movable wall; and

means positioned over the material receiving portion of the conveyor means for cooperation with the cams on the movable walls to pivot the movable walls to the material dumping position against the action of the springs.

26. The excavating and loading system according to claim 17 wherein the movable wall pivoting means further comprises:

a cam track disposed around the axis of rotation of the buckets; and

a plurality of cam followers each connected to one of the movable walls and each operatively engaged with the cam track for actuation thereby to pivot the movable walls between the material receiving and the material dumping positions.

27. The excavating and loading system according to claim 17 wherein the movable wall pivoting means comprises:

a plurality of cylinders each connected to one of the movable walls for actuation under fluid pressure to pivot the movable walls to the material dumping position; and

valve means for controlling the actuation of the cylinders in accordance with the rotational positioning of the digging buckets.

28. The excavating and loading system according to claim 17 further including:

auxiliary conveyor means mounted for pivotal movement about a vertical axis; and

ballast means for selective actuation to counterbalance the auxiliary conveyor means.

29. The excavating and loading system according to claim 28 wherein the vehicle further comprises:

a frame;

means supporting the frame for movement along a surface; and

an engine for actuating the supporting means to propel the vehicle and for actuating the conveyor means and the auxiliory conveyor means;

and wherein the ballast means is further characterized by four ballast tanks positioned at forward and rearward positions on opposite sides of the frame.

30. The excavating and loading system according to claim 29 wherein the excavating wheel means is positioned at one end of the frame, wherein the conveyor means extends rearwardly from the frame between the ballast tanks, and wherein the auxiliary conveyor means is positioned at the opposite end of the frame from the excavating wheel means.

31. The excavating and loading system according to claim 18 wherein the means for directing material from the two outside excavating wheels to the conveyor means includes cross conveyors for transporting excavated material inwardly to the conveyor means.

32. An excavating and loading system comprising:

vehicle means having a main frame and adapted for movement over a surface and having a predetermined length and a predetermined width;

excavating wheel means mounted at the front end of the vehicle means for rotation about an axis extending parallel to the width and perpendicular to the length of the vehicle;

said excavating wheel means comprising axle means,

two rigid side excavating wheels mounted cantilever on the axle means and comprising the outermost structural components of the excavating and loading system. a third rigid excavating wheel supported on the axle means and extending between the two side excavating wheels and spaced. parallel excavating wheel supporting and having means extending between the center and the two side excavating wheels;

means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; each of said excavating wheels further comprising a plurality of digging buckets with the digging buckets of the side excavating wheels spanning continuously from the outer ends of the excavating wheel means to points immediately adjacent the supporting and housing means and with the digging buckets of the center excavating wheel spanning continuously between points immediately adjacent the two supporting and housing means; the digging buckets each comprising a rear wall mounted for movement between a material receiving position and a material discharging position;

means located within the margins of the excavating wheel means and responsive to rotation of the excavating wheel means relative to the vehicle for first positively actuating the movable wall of each digging bucket to the material receiving position and for subsequently positively actuating the movable wall of each digging bucket to the material dis charging position; conveyor means mounted on the vehicle behind the excavating wheel means for receiving material from the center excavating wheel and for carrying the material upwardly and rearwardly to a discharge point at the rear end of the vehicle; and

means mounted on the vehicle behind the excavating wheel means for receiving material from the two side excavating wheels and for directing the material to the conveyor means for transportation thereby to the discharge point.

33. The excavating and loading system according to claim 32 wherein the movable wall actuating means comprises:

a plurality of push rods each connected at one end to the movable wall of one of the buckets;

a chain interconnecting the ends of the push rods remote from the movable walls; and

a member fixedly supported at a point over the material receiving portion of the conveyor means for cooperation with each push rod to move the corresponding movable wall to the material dumping position.

34. The excavating and loading system according to claim 32 wherein the movable wall actuating means comprises:

a plurality of push rods each connected at one end to the movable wall of one of the buckets;

a collar connected to the ends of the push rods remote from the movable walls;

means constraining the push rods to rotation with the buckets; and

means rotatably supporting the collar at a point offset from the axis of rotation of the buckets and thereby actuating the push rods to pivot the movable walls to the material dumping position when their respective buckets are positioned over the material receiving portion of the conveyor means.

35. The excavating and loading system according to claim 32 wherein the movable wall actuating means comprises:

a spring connected to each movable wall for normally positioning the movable wall in the material receiving position;

a cam mounted on each movable wall; and

means positioned over the material receiving portion of the conveyor means for cooperation with the cams on the movable walls to pivot the movable walls to the material dumping position against the action of the springs.

36. The excavating and loading system according to claim 32 wherein the movable wall actuating means further comprises:

a cam track disposed around the axis of rotation of the buckets; and

a plurality of cam followers each connected to one of the movable walls and each operatively engaged with the cam track for actuation thereby to pivot the movable walls between the material receiving and the material dumping positions.

37. The excavating and loading system according to claim 32 wherein the movable wall actuating means comprises:

a plurality of cylinders each connected to one of the movable walls for actuation under fluid pressure to pivot the movable walls to the material dumping position; and

valve means for controlling the actuation of the cylinders in accordance with the rotational positioning of the digging buckets.

38. The excavating and loading system according to claim 32 further including a conveyor frame supported on the main frame of the vehicle and extending angularly upwardly with respect thereto to define a course of the conveyor means, an auxiliary conveyor supported at the rear end of the system for receiving material from the conveyor means, and means supporting the auxiliary conveyor for pivotal movement about a vertical axis.

39. The excavating and loading system according to claim 28 further including a ballast system comprising a plurality of tanks positioned at spaced points on the vehicle and means for selectively pumping liquid between the tanks and thereby counterbalancing the weight of the auxiliary conveyor.

40. The excavating and loading system according to claim 32 further including an auxiliary conveyor for receiving excavated material from the conveyor means and supported for pivotal movement about a vertical axis to control the point of discharge of the material.

41. The excavating and loading system according to claim 40 further including stringer conveyor means mounted on the auxiliary conveyor and means for selectively positioning the stringer conveyor means so that material is either discharged directly from the auxiliary conveyor or is received from the auxiliary conveyor by the stringer conveyor means.

42. The excavating and loading system according to claim 40 wherein the vehicle further comprises:

a frame;

means supporting the frame for movement along a surface; and

an engine for actuating the supporting means to pro pel the vehicle and for actuating the conveyor means and the auxiliary conveyor;

and ballast means including ballast tanks positioned at forward and rearward positions on opposite sides upwardly to a discharge point at the opposite end of the vehicle from the excavating wheels.

44. The excavating and loading system according to claim 32 wherein the vehicle is further characterized by:

a frame;

a plurality of rubber tired wheels supporting the frame for transporting the vehicle over a surface; an engine mounted on the frame; and

means driven by the engine for actuating the rubber tired wheels to propel the vehicle over the surface.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 896 571 Dated July 29 1975 Inventor(s) Charles R. Satterwhite It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Insert the following information on the cover page below the identification of inventor:

"Assignee: Unit Rig & Equipment C0.,

Tulsa, Oklahoma.

Signed and Stalcd this thirteenth Day of April1976 [SEAL] A Ires t:

RUTH C. M ASON C. MARSHALL DANN Anesnng Officer ('mnmissium'r 0f lau'ms and Trademarks 

1. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and at least two rigid excavating wheels rotatably mounted cantilever on and supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets located immediately adjacent one another to define the entire circumference of the excavating wheel, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivoTal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; each of said digging buckets extending continuously between a side wall thereof located immediately adjacent to the supporting means and a side wall thereof defining one end of the excavating wheel assembly; drive means extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each digging bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; and conveyor means mounted on the vehicle entirely behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from the digging buckets of the excavating wheels upon the positioning of the movable walls of the buckets in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the low portion.
 2. The excavating and loading system according to claim 1 wherein the excavating wheel assembly is further characterized by a third rigid excavating wheel positioned between the said at least two excavating wheels and rotatably supported on the axle means.
 3. The excavating and loading system according to claim 2 wherein the conveyor means receives excavated material directly from the center excavating wheel and further including means positioned on the vehicle behind the excavating wheel assembly to receive excavated material from the digging buckets of the outside excavating wheels upon positioning of the movable walls of the digging buckets in the material dumping position and for directing the material to the conveyor means.
 4. The excavating and loading system according to claim 1 further including a third excavating wheel supported on the axle means between the two cantilever supported excavating wheels and wherein the excavating wheel supporting and driving means comprises spaced, parallel excavating wheel supporting and driving means extending between the center and the two side excavating wheels.
 5. The excavating and loading system according to claim 4 wherein the conveyor means receives material from the center excavating wheel and further including means mounted on the vehicle behind the excavating wheel means for receiving material from the two side excavating wheels and for directing the material to the conveyor means for transportation thereby to the discharge point.
 6. The excavating and loading system according to claim 1 further including a conveyor frame supported on the main frame of the vehicle and extending angularly upwardly with respect thereto to define a course of the conveyor means, means supporting the upper portion of the conveyor frame for pivotal movement with respect to the lower portion thereof, an auxiliary conveyor supported at the rear end of the system for receiving material from the conveyor means, and means supporting the auxiliary conveyor for pivotal movement about a vertical axis.
 7. The excavating and loading system according to claim 1 further including a ballast system comprising a plurality of tanks positioned at spaced points on the vehicle and means for selectively pumping liquid between the tanks.
 8. The excavating and loading system according to Claim 1 wherein the movable wall pivoting means comprises: a plurality of push rods each connected at one end to the movable wall of one of the buckets; a chain interconnecting the ends of the push rods remote from the movable walls; and a member fixedly supported at a point over the material receiving portion of the conveyor means for cooperation with each push rod to move the corresponding movable wall to the material dumping position.
 9. The excavating and loading system according to claim 1 wherein the movable wall pivoting means comprises: a plurality of push rods each connected at one end to the movable wall of one of the buckets; a collar connected to the ends of the push rods remote from the movable walls; means constraining the push rods to rotation with the buckets; and means rotatably supporting the collar at a point offset from the axis of rotation of the buckets and thereby actuating the push rods to pivot the movable walls to the material dumping position when their respective buckets are positioned over the material receiving portion of the conveyor means.
 10. The excavating and loading system according to claim 1 wherein the movable wall pivoting means comprises: a spring connected to each movable wall for normally positioning the movable wall in the material receiving position; a cam mounted on each movable wall; and means positioned over the material receiving portion of the conveyor means for cooperation with the cams on the movable walls to pivot the movable walls to the material dumping position against the action of the springs.
 11. The excavating and loading system according to claim 1 wherein the movable wall pivoting means further comprises: a cam track disposed around the axis of rotation of the buckets; and a plurality of cam followers each connected to one of the movable walls and each operatively engaged with the cam track for actuation thereby to pivot the movable walls between the material receiving and the material dumping positions.
 12. The excavating and loading system according to claim 1 wherein the movable wall pivoting means comprises: a plurality of cylinders each connected to one of the movable walls for actuation under fluid pressure to pivot the movable walls to the material dumping position; and valve means for controlling the actuation of the cylinders in accordance with the rotational positioning of the digging buckets.
 13. The excavating and loading system according to claim 1 further including: auxiliary conveyor means mounted on the vehicle for receiving excavated material from the conveyor means and mounted for pivotal movement about a vertical axis; a plurality of ballast tanks; and means for selectively directing liquid between the ballast tanks to counterbalance the weight of the auxiliary conveyor means.
 14. The excavating and loading system according to claim 13 wherein the vehicle further comprises: a frame; means supporting the frame for movement along a surface; and an engine for actuating the supporting means to propel the vehicle and for actuating the conveyor means and the auxiliary conveyor means; and wherein the ballast tanks are further characterized by four ballast tanks positioned at forward and rearward positions on opposite sides of the frame.
 15. The excavating and loading system according to claim 14 wherein the excavating wheel means is positioned at one end of the frame, wherein the conveyor means extends rearwardly from the frame between the ballast tanks, and wherein the auxiliary conveyor means is positioned at the opposite end of the frame from the excavating wheel means.
 16. The excavating system according to claim 1 wherein the conveyor means comprises a pair of cross conveyors mounted on the vehicle adjacent the excavating wheels for receiving material from the excavating wheels and for transporting the material inwardly and a conveyor centrally disposed on the vehIcle for receiving material from the cross conveyors and from the excavating wheels and for transporting the material angularly upwardly to a discharge point at the opposite end of the vehicle from the excavating wheels.
 17. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and three rigid excavating wheels rotatably supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; said three excavating wheels including a center excavating wheel comprising digging buckets spanning continuously between points immediately adjacent to the supporting and housing means and two side excavating wheels each comprising digging buckets spanning continuously from points immediately adjacent to the supporting and housing means to points defining the outer ends of the excavating wheel assembly; means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; conveyor means mounted on the vehicle behind the excavating wheel for movement around a course including a relatively low portion positioned to receive material from each digging bucket of the center excavating wheel upon the positioning of the movable wall of the bucket in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the lower portion; and means positioned on the vehicle behind the excavating wheel assembly to receive material from each digging bucket of the outside excavating wheels upon the positioning of the movable wall of the bucket in the material dumping position and for directing the material to the conveyor means.
 18. The excavating and loading system according to claim 17 wherein the conveyor means is further characterized by a conveyor frame mounted on the vehicle and extending generally angularly upwardly with respect thereto to define the course of the conveyor means and including a lower fixedly supported portion and an upper portion mounted for pivotal movement about a horizontal axis.
 19. The excavating and loading system according to claim 17 further including an auxiliary conveyor mounted beneath the high delivery portion of the conveyor means for receiving material therefrom, and means for selectively pivoting the auxiliary conveyor about a vertical axis.
 20. The excavating and loading system according to claim 17 wherein the vehicle comprises: a main frame; a plurality of pneumatic tired wheels for supporting the main frame; and an engine mounted on the main frame for propelling the system by means of the wheels and for actuating the conveyor means independently of the operation of the excavating wheel supporting and rotating means.
 21. The excavating and loading system according to claim 17 further including a conveyor frame supported oN the main frame of the vehicle and extending angularly upwardly with respect thereto to define a course of the conveyor means, means supporting the upper portion of the conveyor frame for pivotal movement with respect to the lower portion thereof, an auxiliary conveyor supported at the rear end of the system for receiving material from the conveyor means, and means supporting the auxiliary conveyor for pivotal movement about a vertical axis.
 22. The excavating and loading system according to claim 21 further including a ballast system comprising a plurality of tanks positioned at spaced points on the vehicle and means for selectively pumping liquid between the tanks and thereby counterbalancing the weight of the auxiliary conveyor.
 23. The excavating and loading system according to claim 17 wherein the movable wall pivoting means comprises: a plurality of push rods each connected at one end to the movable wall of one of the buckets; a chain interconnecting the ends of the push rods remote from the movable walls; and a member fixedly supported at a point over the material receiving portion of the conveyor means for cooperation with each push rod to move the corresponding movable wall to the material dumping position.
 24. The excavating and loading system according to claim 17 wherein the movable wall pivoting means comprises: a plurality of push rods each connected at one end to the movable wall of one of the buckets; a collar connected to the ends of the push rods remote from the movable walls; means constraining the push rods to rotation with the buckets; and means rotatably supporting the collar at a point offset from the axis of rotation of the buckets and thereby actuating the push rods to pivot the movable walls to the material dumping position when their respective buckets are positioned over the material receiving portion of the conveyor means.
 25. The excavating and loading system according to claim 17 wherein the movable wall pivoting means comprises: a spring connected to each movable wall for normally positioning the movable wall in the material receiving position; a cam mounted on each movable wall; and means positioned over the material receiving portion of the conveyor means for cooperation with the cams on the movable walls to pivot the movable walls to the material dumping position against the action of the springs.
 26. The excavating and loading system according to claim 17 wherein the movable wall pivoting means further comprises: a cam track disposed around the axis of rotation of the buckets; and a plurality of cam followers each connected to one of the movable walls and each operatively engaged with the cam track for actuation thereby to pivot the movable walls between the material receiving and the material dumping positions.
 27. The excavating and loading system according to claim 17 wherein the movable wall pivoting means comprises: a plurality of cylinders each connected to one of the movable walls for actuation under fluid pressure to pivot the movable walls to the material dumping position; and valve means for controlling the actuation of the cylinders in accordance with the rotational positioning of the digging buckets.
 28. The excavating and loading system according to claim 17 further including: auxiliary conveyor means mounted for pivotal movement about a vertical axis; and ballast means for selective actuation to counterbalance the auxiliary conveyor means.
 29. The excavating and loading system according to claim 28 wherein the vehicle further comprises: a frame; means supporting the frame for movement along a surface; and an engine for actuating the supporting means to propel the vehicle and for actuating the conveyor means and the auxiliory conveyor means; and wherein the ballast means is further characterized by four ballast tanks positioned at forward and rearward positions on opposite sides of the frame.
 30. The excavating and loading system according to claim 29 wherein the excavating wheel means is positioned at one end of the frame, wherein the conveyor means extends rearwardly from the frame between the ballast tanks, and wherein the auxiliary conveyor means is positioned at the opposite end of the frame from the excavating wheel means.
 31. The excavating and loading system according to claim 18 wherein the means for directing material from the two outside excavating wheels to the conveyor means includes cross conveyors for transporting excavated material inwardly to the conveyor means.
 32. An excavating and loading system comprising: vehicle means having a main frame and adapted for movement over a surface and having a predetermined length and a predetermined width; excavating wheel means mounted at the front end of the vehicle means for rotation about an axis extending parallel to the width and perpendicular to the length of the vehicle; said excavating wheel means comprising axle means, two rigid side excavating wheels mounted cantilever on the axle means and comprising the outermost structural components of the excavating and loading system, a third rigid excavating wheel supported on the axle means and extending between the two side excavating wheels and spaced, parallel excavating wheel supporting and having means extending between the center and the two side excavating wheels; means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; each of said excavating wheels further comprising a plurality of digging buckets with the digging buckets of the side excavating wheels spanning continuously from the outer ends of the excavating wheel means to points immediately adjacent the supporting and housing means and with the digging buckets of the center excavating wheel spanning continuously between points immediately adjacent the two supporting and housing means; the digging buckets each comprising a rear wall mounted for movement between a material receiving position and a material discharging position; means located within the margins of the excavating wheel means and responsive to rotation of the excavating wheel means relative to the vehicle for first positively actuating the movable wall of each digging bucket to the material receiving position and for subsequently positively actuating the movable wall of each digging bucket to the material discharging position; conveyor means mounted on the vehicle behind the excavating wheel means for receiving material from the center excavating wheel and for carrying the material upwardly and rearwardly to a discharge point at the rear end of the vehicle; and means mounted on the vehicle behind the excavating wheel means for receiving material from the two side excavating wheels and for directing the material to the conveyor means for transportation thereby to the discharge point.
 33. The excavating and loading system according to claim 32 wherein the movable wall actuating means comprises: a plurality of push rods each connected at one end to the movable wall of one of the buckets; a chain interconnecting the ends of the push rods remote from the movable walls; and a member fixedly supported at a point over the material receiving portion of the conveyor means for cooperation with each push rod to move the corresponding movable wall to the material dumping position.
 34. The excavating and loading system according to claim 32 wherein the movable wall actuating means comprises: a plurality of push rods each connected at one end to the movable wall of one of the buckets; a collar connected to the ends of the push rods remote from the movable walls; means constraining the push rods to rotation with the buckets; and means rotatably supporting the collar at a point offset from the axis of rotation of the buckets and thereby actuaTing the push rods to pivot the movable walls to the material dumping position when their respective buckets are positioned over the material receiving portion of the conveyor means.
 35. The excavating and loading system according to claim 32 wherein the movable wall actuating means comprises: a spring connected to each movable wall for normally positioning the movable wall in the material receiving position; a cam mounted on each movable wall; and means positioned over the material receiving portion of the conveyor means for cooperation with the cams on the movable walls to pivot the movable walls to the material dumping position against the action of the springs.
 36. The excavating and loading system according to claim 32 wherein the movable wall actuating means further comprises: a cam track disposed around the axis of rotation of the buckets; and a plurality of cam followers each connected to one of the movable walls and each operatively engaged with the cam track for actuation thereby to pivot the movable walls between the material receiving and the material dumping positions.
 37. The excavating and loading system according to claim 32 wherein the movable wall actuating means comprises: a plurality of cylinders each connected to one of the movable walls for actuation under fluid pressure to pivot the movable walls to the material dumping position; and valve means for controlling the actuation of the cylinders in accordance with the rotational positioning of the digging buckets.
 38. The excavating and loading system according to claim 32 further including a conveyor frame supported on the main frame of the vehicle and extending angularly upwardly with respect thereto to define a course of the conveyor means, an auxiliary conveyor supported at the rear end of the system for receiving material from the conveyor means, and means supporting the auxiliary conveyor for pivotal movement about a vertical axis.
 39. The excavating and loading system according to claim 28 further including a ballast system comprising a plurality of tanks positioned at spaced points on the vehicle and means for selectively pumping liquid between the tanks and thereby counterbalancing the weight of the auxiliary conveyor.
 40. The excavating and loading system according to claim 32 further including an auxiliary conveyor for receiving excavated material from the conveyor means and supported for pivotal movement about a vertical axis to control the point of discharge of the material.
 41. The excavating and loading system according to claim 40 further including stringer conveyor means mounted on the auxiliary conveyor and means for selectively positioning the stringer conveyor means so that material is either discharged directly from the auxiliary conveyor or is received from the auxiliary conveyor by the stringer conveyor means.
 42. The excavating and loading system according to claim 40 wherein the vehicle further comprises: a frame; means supporting the frame for movement along a surface; and an engine for actuating the supporting means to propel the vehicle and for actuating the conveyor means and the auxiliary conveyor; and ballast means including ballast tanks positioned at forward and rearward positions on opposite sides of the frame for selective actuation to counterbalance the auxiliary conveyor.
 43. The excavating system according to claim 32 wherein the means for directing excavated material to the conveyor means comprises a pair of cross conveyors mounted on the vehicle adjacent the excavating wheels for receiving material from the side excavating wheels and for transporting the material inwardly and wherein the conveyor means includes a conveyor centrally disposed on the vehicle for receiving material from the cross conveyors and from the center excavating wheel and for transporting the material angularly upwardly to a discharge point at the opposite end of the vehicle from the excavating wheels.
 44. The excavating and loading system according to claim 32 wherein the vehicle is further characterized by: a frame; a plurality of rubber tired wheels supporting the frame for transporting the vehicle over a surface; an engine mounted on the frame; and means driven by the engine for actuating the rubber tired wheels to propel the vehicle over the surface. 